Average. Average Variation Sound 0.167 sec. 0.0221 sec. Light 0.222 sec. 0.0219 sec. Electric skin-sensation 0.201 sec. 0.0115 sec. Touch-sensations 0.213 sec. 0.0134 sec. "I here bring together the averages which have been obtained by some other observers: Hirsch. Hankel. Exner. Sound 0.149 0.1505 0.1360 Light 0.200 0.2246 0.1506 Skin-sensation 0.182 0.1546 0.1337"[124] _Thermic_ reactions have been lately measured by A. Goldscheider and by Vintschgau (1887), who find them slower than reactions from touch. That from heat especially is very slow, more so than from cold, the differences (according to Goldscheider) depending on the nerve-terminations in the skin. _Gustatory_ reactions were measured by Vintschgau. They differed according to the substances used, running up to half a second as a maximum when identification took place. The mere perception of the presence of the substance on the tongue varied from 0''.159 to 0''.219 (Pflüger's Archiv, xiv, 529). _Olfactory_ reactions have been studied by Vintschgau, Buccola, and Beaunis. They are slow, averaging about half a second (cf. Beaunis, Recherches exp. sur l'Activité Cérébrale, 1884, p. 49 ff.). It will be observed that _sound_ is more promptly reacted on than either _sight_ or _touch. Taste_ and _smell_ are slower than either. One individual, who reacted to touch upon the tip of the tongue in 0''.125, took 0''.993 to react upon the taste of quinine applied to the same spot. In another, upon the base of the tongue, the reaction to touch being 0''.141, that to sugar was 0''.552 (Vintschgau, quoted by Buccola, p. 103). Buccola found the reaction to odors to vary from 0''.334 to 0''.681, according to the perfume used and the individual. The _intensity of the signal_ makes a difference. The intenser the stimulus the shorter the time. Herzen (Grundlinien einer allgem. Psychophysiologie, p. 101) compared the reaction from a _corn_ on the toe with that from the skin of the hand of the same subject. The two places were stimulated simultaneously, and the subject tried to react simultaneously with both hand and foot, but the foot always went quickest. When the sound skin of the foot was touched instead of the corn, it was the hand which always reacted first. Wundt tries to show that when the signal is made barely perceptible, the time is probably the same in all the senses, namely, about 0.332'' (Physiol. Psych., 2d ed., ii, 224).